Liberia's central bank board has elected the son of Nobel Peace Prize winning President Ellen Johnson Sirleaf as its interim executive governor, bank sources said on Wednesday.

Charles Sirleaf, formerly a deputy governor who has worked for the bank since 2004, will occupy the post for an undefined interim period. The previous head, Joseph Mills Jones, left to prepare his candidacy for a presidential election in the West African country due to take place in 2017.

President Johnson Sirleaf, who has strong ties with Washington and is credited with helping the country recover from a bloody civil war that ended in 2003, must step down next year due to a two-term limit.

She is due to decide on a permanent successor to Jones, to steer Liberia's economic recovery after two years in which the country endured an Ebola epidemic and a collapse in the price of iron ore, its major export earner.

A source close to the presidency confirmed the temporary appointment, without giving an indication of how long he would remain.

Some critics accuse Johnson Sirleaf of appointing family members and other allies to key posts throughout her presidency in order to consolidate her position.

Another one of her sons, Robert, was both chairman of the National Oil Company of Liberia and senior adviser to the president until he resigned in 2013. Fumba Sirleaf, her stepson, is the head of the National Security Agency.

"This (appointment at the central bank) is unfair. It is not about qualifications, but about expediency," said Emmanuel Gonquoi, former chairman for the coalition of civil society in Liberia and a political commentator.

However, central bank officials stressed that Charles Sirleaf was a suitable choice.

"Charles is competent and qualified for the position," said one, who asked for anonymity since he is not qualified to speak with the media.